Simsons Simsons - 1 year ago 123
C++ Question

cannot convert from 'std::string' to 'LPSTR'

As I clould not pass LPCSTR from one function to another (Data get changed) I tried passing it as a string.

But later I need to again convert it back to LPSTR. While trying the conversion I am getting the above error:

cannot convert from 'std::string' to 'LPSTR'

How can I resolve this?

Answer Source

That's just because you should use std::string::c_str() method.

But this involves const_cast in given case because const char * returned by c_str() can not be assigned to a non-constant LPSTR.

std::string str = "something";
LPSTR s = const_cast<char *>(str.c_str());

But you must be sure that lifetime of str will be longer that that of LPTSTR variable.

Another mention, if code compiles as Unicode-conformant, then types LPTSTR and std::string are incompatible. You should use std::wstring instead.

Important note: If you pass the resulting pointer s from above to a function which tries to modify the data it is pointing to this will result in undefined behaviour. The only way to properly deal with it is to duplicate the string into a non-const buffer (e.g. via strdup)

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